The contribution of cholesterol and epigenetic changes to the pathophysiology of breast cancer

Cholesterol and Cytokines: Molecular Links to Atherosclerosis and Carcinogenesis

An increase of cholesterol concentration within the artery obstructs arterial blood flow once it deposits alongside the arterial wall. This results in atherosclerosis. Carcinogenesis causes a quicker clearance of vascular cholesterol to meet the demands of tumour cell development. Both illnesses have an increased concentration of pro-inflammatory cytokines in the blood. To search the comparative characteristics of cholesterol and pro-inflammatory cytokines in the pathogenesis of atherosclerosis and carcinogenesis, a comprehensive online survey using MEDLINE, Scopus, PubMed, and Google Scholar was conducted for relevant journals with key search term cholesterol and cytokines in atherosclerotic and cancerous patients. According to reports, hypercholesterolaemia related dyslipidemia causes atherosclerosis in blood arteries and hypercholesterolaemia in cell nucleus is a reason for developing carcinogenesis. It is also noted that pro-inflammatory cytokines are involved in both of the aforementioned pathogenesis. Changes in anti-inflammatory cytokines are only the characteristic features of each kind. Thus, Cholesterol and pro-inflammatory cytokines are intensely interlinked in the genesis of atherosclerotic and carcinogenic consequences.

Oestrogen receptor positive breast cancer and its embedded mechanism: breast cancer resistance to conventional drugs and related therapies, a review

Traditional medication and alternative therapies have long been used to treat breast cancer. One of the main problems with current treatments is that there is an increase in drug resistance in the cancer cells owing to genetic differences such as mutational changes, epigenetic changes and miRNA (microRNA) alterations such as miR-1246, miR-298, miR-27b and miR-33a, along with epigenetic modifications, such as Histone3 acetylation and CCCTC-Binding Factor (CTCF) hypermethylation for drug resistance in breast cancer cell lines. Certain forms of conventional drug resistance have been linked to genetic changes in genes such as ABCB1, AKT, S100A8/A9, TAGLN2 and NPM. This review aims to explore the current approaches to counter breast cancer, the action mechanism, along with novel therapeutic methods endowing potential drug resistance. The investigation of novel therapeutic approaches sheds light on the phenomenon of drug resistance including genetic variations that impact distinct forms of oestrogen receptor (ER) cancer, genetic changes, epigenetics-reported resistance and their identification in patients. Long-term effective therapy for breast cancer includes selective oestrogen receptor modulators, selective oestrogen receptor degraders and genetic variations, such as mutations in nuclear genes, epigenetic modifications and miRNA alterations in target proteins. Novel research addressing combinational therapies including maytansine, photodynamic therapy, guajadiol, talazoparib, COX2 inhibitors and miRNA 1246 inhibitors have been developed to improve patient survival rates.

Epigenetic Dysregulation and Its Correlation with the Steroidogenic Machinery Impacting Breast Pathogenesis: Data Mining and Molecular Insights into Therapeutics

Breast cancer (BC) is a heterogeneous condition and comprises molecularly distinct subtypes. An imbalance in the levels of epigenetic histone deacetylases (HDACs), modulating estrogen accumulation, especially 17β-estradiol (E2), promotes breast tumorigenesis. In the present study, analyses of The Cancer Genome Atlas (TCGA) pan-cancer normalized RNA-Seq datasets revealed the dysregulation of 16 epigenetic enzymes (among a total of 18 members) in luminal BC subtypes, in comparison to their non-cancerous counterparts. Explicitly, genomic profiling of these epigenetic enzymes displayed increases in HDAC1, 2, 8, 10, 11, and Sirtuins (SIRTs) 6 and 7, and decreases in HDAC4-7, -9, and SIRT1-4 levels, respectively, in TCGA breast tumors. Kaplan-Meier plot analyses showed that these HDACs, with the exception of HDAC2 and SIRT2, were not correlated with the overall survival of BC patients. Additionally, disruption of the epigenetic signaling in TCGA BC subtypes, as assessed using both heatmaps and boxplots, was associated with the genomic expression of factors that are instrumental for cholesterol trafficking/utilization for accelerating estrogen/E2 levels, in which steroidogenic acute regulatory protein (STAR) mediates the rate-limiting step in steroid biosynthesis. TCGA breast samples showed diverse expression patterns of a variety of key steroidogenic markers and hormone receptors, including LIPE, CYP27A1, STAR, STARD3, CYP11A1, CYP19A1, ER, PGR, and ERBB2. Moreover, regulation of STAR-governed steroidogenic machinery was found to be influenced by various transcription factors, i.e., CREB1, CREM, SF1, NR4A1, CEBPB, SREBF1, SREBF2, SP1, FOS, JUN, NR0B1, and YY1. Along these lines, ingenuity pathway analysis (IPA) recognized a number of new targets and downstream effectors influencing BCs. Of note, genomic, epigenomic, transcriptional, and hormonal anomalies observed in human primary breast tumors were qualitatively similar in pertinent BC cell lines. These findings identify the functional correlation between dysregulated epigenetic enzymes and estrogen/E2 accumulation in human breast tumors, providing the molecular insights into more targeted therapeutic approaches involving the inhibition of HDACs for combating this life-threatening disease.

Simvastatin prevents BMP-2 driven cell migration and invasion by suppressing oncogenic DNMT1 expression in breast cancer cells

Both epigenetic and genetic changes in the cancer genome act simultaneously to promote tumor development and metastasis. Aberrant DNA methylation, a prime epigenetic event, is often observed in various cancer types. The elevated DNA methyltransferase 1 (DNMT1) enzyme creates DNA hypermethylation at CpG islands to drive oncogenic potential. This study emphasized to decipher the molecular mechanism of endogenous regulation of DNMT1 expression for finding upstream signaling molecules. Cancer database analyses found an upregulated DNMT1 expression in most cancer types including breast cancer. Overexpression of DNMT1 showed an increased cell migration, invasion, and stemness potential whereas 5-azacytidine (DNMT1 inhibitor) and siRNA mediated knockdown of DNMT1 exhibited inhibition of such cancer activities in breast cancer MDA-MB-231 and MCF-7 cells. Infact, cancer database analyses further found a positive correlation of DNMT1 transcript with both cholesterol pathway regulatory genes and BMP signaling molecules. Experimental observations documented that the cholesterol-lowering drug, simvastatin decreased DNMT1 transcript as well as protein, whereas BMP-2 treatment increased DNMT1 expression in breast cancer cells. In addition, expression of various key cholesterol regulatory genes was found to be upregulated in response to BMP-2 treatment. Moreover, simvastatin inhibited BMP-2 induced DNMT1 expression in breast cancer cells. Thus, this study for the first time reveals that both BMP-2 signaling and cholesterol pathways could regulate endogenous DNMT1 expression in cancer cells.

Increased plasma lipids in triple-negative breast cancer and impairment in HDL functionality in advanced stages of tumors

The association between plasma lipids and breast cancer (BC) has been extensively explored although results are still conflicting especially regarding the relationship with high-density lipoprotein cholesterol (HDLc) levels. HDL mediates cholesterol and oxysterol removal from cells limiting sterols necessary for tumor growth, inflammation, and metastasis and this may not be reflected by measuring HDLc. We addressed recently diagnosed, treatment-naïve BC women (n = 163), classified according to molecular types of tumors and clinical stages of the disease, in comparison to control women (CTR; n = 150) regarding plasma lipids and lipoproteins, HDL functionality and composition in lipids, oxysterols, and apo A-I. HDL was isolated by plasma discontinuous density gradient ultracentrifugation. Lipids (total cholesterol, TC; triglycerides, TG; and phospholipids, PL) were determined by enzymatic assays, apo A-I by immunoturbidimetry, and oxysterols (27, 25, and 24-hydroxycholesterol), by gas chromatography coupled with mass spectrometry. HDL-mediated cell cholesterol removal was determined in macrophages previously overloaded with cholesterol and ¹⁴C-cholesterol. Lipid profile was similar between CTR and BC groups after adjustment per age. In the BC group, lower concentrations of TC (84%), TG (93%), PL (89%), and 27-hydroxicholesterol (61%) were observed in HDL, although the lipoprotein ability in removing cell cholesterol was similar to HDL from CRT. Triple-negative (TN) BC cases presented higher levels of TC, TG, apoB, and non-HDLc when compared to other molecular types. Impaired HDL functionality was observed in more advanced BC cases (stages III and IV), as cholesterol efflux was around 28% lower as compared to stages I and II. The altered lipid profile in TN cases may contribute to channeling lipids to tumor development in a hystotype with a more aggressive clinical history. Moreover, findings reinforce the dissociation between plasma levels of HDLc and HDL functionality in determining BC outcomes.

The critical role of the phytosterols in modulating tumor microenvironment via multiple signaling: A comprehensive molecular approach

Cancer is the leading cause of mortality and morbidity worldwide, and its cases are rapidly increasing every year. Several factors contribute to the development of tumorigenesis. including radiation, dietary lifestyle, smoking, environmental, and genetic factors. The cell cycle is regulated by a variety of molecular signaling proteins. However, when the proteins involved in the cell cycle regulation are altered, cellular growth and proliferation are significantly affected. Natural products provide an important source of new drug development for a variety of ailments. including cancer. Phytosterols (PSs) are an important class of natural compounds reported for numerous pharmacological activities, including cancer. Various PSs, such as ergosterol, stigmasterol, sitosterol, withaferin A, etc., have been reported for their anti-cancer activities against a variety of cancer by modulating the tumor microenvironment via molecular signaling pathways discussed within the article. These signaling pathways are associated with the production of pro-inflammatory mediators, growth factors, chemokines, and pro-apoptotic and anti-apoptotic genes. These mediators and their upstream signaling are very active within the variety of tumors and by modulating these signalings, thus PS exhibits promising anti-cancer activities. However, further high-quality studies are needed to firmly establish the clinical efficacy as well the safety of the phytosterols.

Preoperative Naples prognostic score is a reliable prognostic indicator for newly diagnosed glioblastoma patients

Background

Glioblastoma (GBM) accounts for approximately 80% of malignant gliomas and is characterized by considerable cellularity and mitotic activity, vascular proliferation, and necrosis. Naples prognostic score (NPS), based on inflammatory markers and nutritional status, has a prognostic ability in various cancers. In the current study, we aim to explore the prognostic value of operative NPS in GBM patients and compare the prognostic ability between NPS and controlling nutritional status (CONUT).

Materials and methods

The retrospective analysis was carried out on consecutive newly diagnosed GBM patients who had underwent tumor resection at West China Hospital from February 2016 to March 2019. All statistical analyses were conducted using SPSS software and R software.

Results

A total of 276 newly diagnosed GBM patients were enrolled in the current study. Overall survival (OS) (p < 0.001) and tumor location (p = 0.007) were significantly related to NPS. Serum albumin concentrate, cholesterol concentrate, neutrophil-to-lymphocyte ratio, lymphocyte ratio, and CONUT score were all significantly associated with NPS (p < 0.001). The Kaplan–Meier curve indicated that NPS (log-rank test, p < 0.001) and CONUT score (log-rank test, p = 0.023) were significantly associated with OS. Multivariate Cox regression revealed that both NPS and CONUT score served as independent prognostic indicators. The prognostic model with NPS had the strongest prognostic capability and best model-fitting.

Conclusion

In the current study, NPS is found as an independent prognostic indicator for patients with newly diagnosed GBM, and the prognostic ability of NPS is superior to CONUT score.

Mitophagy-mediated molecular subtypes depict the hallmarks of the tumour metabolism and guide precision chemotherapy in pancreatic adenocarcinoma

Background: Mitophagy is closely related to cancer initiation and progression. However, heterogeneity with reference to mitophagy remains unexplored in pancreatic adenocarcinoma (PAAD).

Materials and methods: We used Reactome database to download the mitophagy-related, glycolysis-related and cholesterol biosynthesis-related signaling pathways. Unsupervised clustering using the “ConsensusClusterPlus” R package was performed to identify molecular subtypes related to mitophagy and metabolism. Prognosis-related mitophagy regulators were identified by univariate Cox regression analysis. Receiver operating characteristics (ROC) and Kaplan-Meier (K-M) survival analyses were used to assess the diagnostic and prognostic role of the hub genes and prognosis risk model. Weighted gene co-expression network analysis (WGCNA) was utilized for screening the mitophagy subtype-related hub genes. Metascape was utilized to carry out functional enrichment analysis. The “glmnet” R package was utilised for LASSO, and the “e1071” R package was utilised for SVM. Chemotherapeutic drug sensitivity was estimated using the R package “pRRophetic” and Genomics of Drug Sensitivity in Cancer (GDSC) database. The nomogram was established by the “rms” R package.

Results: Three distinct mitophagy subtypes (low, high and intermediate) of PAAD were identified based on the landscape of mitophagy regulators. The high mitophagy subtype had the worst prognosis, highest mRNA expression-based stemness index scores and most hypoxic environment compared to the other subtypes. Additionally, glycolysis and cholesterol biosynthesis were significantly elevated. Three mitophagy subtype-specific gene signatures (CAST, CCDC6, and ERLIN1) were extracted using WGCNA and machine learning. Moreover, PAAD tumours were insensitive to Erlotinib, Sunitinib and Imatinib in the high mitophagy subtype and high CAST, CCDC6, and ERLIN1 expressed subtypes. Furthermore, CAST, CCDC6, and ERLIN1 affected immune cell infiltration (M1 and CD8Tcm), resulting in the altered prognosis of patients with PAAD. A nomogram was constructed to screen patients with the low mitophagy subtype, which showed a higher sensitivity to chemotherapeutic agents.

Conclusion: Based on various bioinformatics tools and databases, the PAAD heterogeneity regarding mitophagy was systematically examined. Three different PAAD subtypes having different outcomes, metabolism patterns and chemosensitivity were observed. Moreover, three novel biomarkers that are closely associated with mitophagy and have the potential to guide individualised treatment regimens in PAAD were obtained.

Lipid Metabolism and Cancer

Lipid metabolism is involved in the regulation of numerous cellular processes, such as cell growth, proliferation, differentiation, survival, apoptosis, inflammation, movement, membrane homeostasis, chemotherapy response, and drug resistance. Reprogramming of lipid metabolism is a typical feature of malignant tumors. In a variety of cancers, fat uptake, storage and fat production are up-regulated, which in turn promotes the rapid growth, invasion, and migration of tumors. This paper systematically summarizes the key signal transduction pathways and molecules of lipid metabolism regulating tumors, and the role of lipid metabolism in programmed cell death. In conclusion, understanding the potential molecular mechanism of lipid metabolism and the functions of different lipid molecules may facilitate elucidating the mechanisms underlying the occurrence of cancer in order to discover new potential targets for the development of effective antitumor drugs.

Targeting of Mevalonate-Isoprenoid Pathway in Acute Myeloid Leukemia Cells by Bisphosphonate Drugs

Metabolic reprogramming represents a hallmark of tumorigenesis to sustain survival in harsh conditions, rapid growth and metastasis in order to resist to cancer therapies. These metabolic alterations involve glucose metabolism, known as the Warburg effect, increased glutaminolysis and enhanced amino acid and lipid metabolism, especially the cholesterol biosynthesis pathway known as the mevalonate pathway and these are upregulated in several cancer types, including acute myeloid leukemia (AML). In particular, it was demonstrated that the mevalonate pathway has a pivotal role in cellular transformation. Therefore, targeting this biochemical process with drugs such as statins represents a promising therapeutic strategy to be combined with other anticancer treatments. In the last decade, several studies have revealed that amino-bisphosphonates (BP), primarily used for bone fragility disorders, also exhibit potential anti-cancer activity in leukemic cells, as well as in patients with symptomatic multiple myeloma. Indeed, these compounds inhibit the farnesyl pyrophosphate synthase, a key enzyme in the mevalonate pathway, reducing isoprenoid formation of farnesyl pyrophosphate and geranylgeranyl pyrophosphate. This, in turn, inhibits the prenylation of small Guanosine Triphosphate-binding proteins, such as Ras, Rho, Rac, Rab, which are essential for regulating cell survival membrane ruffling and trafficking, interfering with cancer key signaling events involved in clonal expansion and maturation block of progenitor cells in myeloid hematological malignancies. Thus, in this review, we discuss the recent advancements about bisphosphonates’ effects, especially zoledronate, analyzing the biochemical mechanisms and anti-tumor effects on AML model systems. Future studies will be oriented to investigate the clinical relevance and significance of BP treatment in AML, representing an attractive therapeutic strategy that could be integrated into chemotherapy.

Chronic Activation of LXRα Sensitizes Mice to Hepatocellular Carcinoma

The oxysterol receptor liver X receptor (LXR) is a nuclear receptor best known for its function in the regulation of lipid and cholesterol metabolism. LXRs, both the α and β isoforms, have been suggested as potential therapeutic targets for several cancer types. However, there was a lack of report on whether and how LXRα plays a role in the development of hepatocellular carcinoma (HCC). In the current study, we found that systemic activation of LXRα in the VP-LXRα knock-in (LXRαKI) mice or hepatocyte-specific activation of LXRα in the VP-LXRα transgenic mice sensitized mice to liver tumorigenesis induced by the combined treatment of diethylnitrosamine (DEN) and 3,3',5,5'-tetrachloro-1,4-bis (pyridyloxy) benzene (TCPOBOP). Mechanistically, the LXRα-responsive up-regulation of interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) signaling pathway and the complement system, and down-regulation of bile acid metabolism, may have contributed to increased tumorigenesis. Accumulations of secondary bile acids and oxysterols were found in both the serum and liver tissue of LXRα activated mice. We also observed an induction of monocytic myeloid-derived suppressor cells accompanied by down-regulation of dendritic cells and cytotoxic T cells in DEN/TCPOBOP-induced liver tumors, indicating that chronic activation of LXRα may have led to the activation of innate immune suppression. The HCC sensitizing effect of LXRα activation was also observed in the c-MYC driven HCC model. Conclusion: Our results indicated that chronic activation of LXRα promotes HCC, at least in part, by promoting innate immune suppressor as a result of accumulation of oxysterols, as well as up-regulation of the IL-6/Janus kinase/STAT3 signaling and complement pathways.

Dietary Intake is Associated with miR-31 and miR-375 Expression in Patients with Head and Neck Squamous Cell Carcinoma

MicroRNAs (miRNAs) are important epigenetic regulators in head and neck squamous cell carcinoma (HNSCC), with miR-31 being considered an oncomir and miR-375, a tumor suppressor miR, which are up- and down-regulated in HNSCC, respectively. Nutrients are known to influence miRNA expression; however, this association is poorly explored in HNSCC. This work aimed to identify associations between dietary intake and the expression of miR-31 and miR-375 in patients newly diagnosed with HNSCC. The expression of miR-31 was positively associated with the consumption of iron (β = 16.65) and vitamin C (β = 0.37), and inversely associated with total sugar (β = -0.88), cholesterol (β= -0.23), vitamin B₉ (β= -0.37) and zinc (β = -5.66) intake. The expression of miR-375 was positively associated with the consumption of selenium (β = 1.52), vitamin C (β = 0.17) and vitamin D (β = 13.01), and inversely associated with the consumption of added sugar (β = -0.49), phosphorus (β= -0.27) and vitamin B₁₂ (β = -10.80). Our findings showed important associations between dietary intake and miR-31 and miR-375 expression in HNSCC, offering possible directions for further studies investigating how nutrients interfere with carcinogenesis.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1990972 .

Preoperative Alkaline Phosphatase-to-Cholesterol Ratio as a Predictor of Overall Survival in Pancreatic Ductal Adenocarcinoma Patients Undergoing Radical Pancreaticoduodenectomy

Background

The value of alkaline phosphatase and cholesterol for predicting overall survival (OS) in cancer patients has been previously studied. However, the predictive value of these variables in patients with pancreatic ductal adenocarcinoma (PDAC) was limited. Hence, we conducted this study to investigate the prognostic value of the alkaline phosphatase-to-cholesterol ratio (ACR) in patients undergoing radical pancreaticoduodenectomy (PD) for PDAC.

Material/Methods

A total of 102 PDAC patients undergoing radical PD at the Cancer Hospital Chinese Academy of Medical Sciences were retrospectively enrolled based on medical records from June 2009 to June 2019. R programming language was used for the optimal cutoff value of biological markers such as preoperative ACR. Kaplan-Meier method and log-rank test were used for univariate survival analysis, and a Cox regression model was used for multivariate survival analysis.

Results

The optimal cutoff value of preoperative ACR was 32.988. Patients with higher preoperative ACR values had worse OS (P<0.001). Higher preoperative ACR was significantly correlated with the degree of tumor differentiation (P<0.018); levels of alanine aminotransferase (P<0.001), aspartate aminotransferase (P<0.001), total bilirubin (P<0.001), and carbohydrate antigen 19-9 (P=0.016); and clinical symptoms (P=0.001). Multivariate analysis showed that tumor differentiation (P<0.001), ACR value (hazard ratio [HR]: 2.225, 95% confidence interval [CI]: 1.33–3.724, P=0.002), and sex (HR, 1.725, 95% CI: 1.1–2.704, P=0.018) were independent factors associated with the prognosis of PDAC patients undergoing radical PD.

Conclusions

The preoperative ACR was correlated with OS in pancreatic cancer patients undergoing radical pancreaticoduodenectomy. Elevated ACR was correlated with poor OS.

27-Hydroxycholesterol-induced EndMT acts via STAT3 signaling to promote breast cancer cell migration by altering the tumor microenvironment

Objective: The endothelial to mesenchymal transition (EndMT) plays a major role in cancer metastasis by regulating the complexity of the tumor microenvironment (TME). Here, we investigated whether 27-hydroxycholesterol (27HC) induces EndMT in endothelial cells (ECs).

Methods: EndMT markers in the human microvascular endothelial cell-1 (HMEC-1) cell line and human umbilical vein endothelial cells (HUVECs) stimulated with 27HC were evaluated with Western blot. Epithelial to mesenchymal transition (EMT) markers in breast cancer (BC) cells cultured in conditioned medium were investigated with quantitative real time polymerase chain reaction (qRT-PCR). The MMP-2 and MMP-9 mRNA expression and activity were detected with qRT-PCR and gelatin zymography assays, respectively. The effect of activated STAT3 on 27HC-induced EndMT was validated by Western blot, immunofluorescence staining, and cell transfection assays. The migration ability of BC cells was evaluated with Transwell assays.

Results: We found that 27HC induced EndMT in HMEC-1 and HUVECs, and 27HC-induced EndMT facilitated EMT and BC cell migration. The 27HC-induced EMT of BC cells also promoted EndMT and HUVEC migration. Investigation of the underlying molecular mechanisms revealed that STAT3 knockdown repressed EndMT in HUVECs as well as migration in BC cells induced with 27HC. In addition, C646 and resveratrol, inhibitors of STAT3 acetylation, repressed the expression of Ac-STAT3, p-STAT3, and EndMT markers in HUVECs exposed to 27HC; these HUVECs in turn attenuated the migration ability of BC cells in 27HC-induced EndMT.

Conclusions: Cross-talk between 27HC-induced EndMT and EMT was observed in the TME. Moreover, activation of STAT3 signaling was found to be involved in 27HC-induced EndMT.

KMT2C is a potential biomarker of prognosis and chemotherapy sensitivity in breast cancer

PURPOSE

Epigenetic regulation plays critical roles in cancer progression, and high-frequency mutations or expression variations in epigenetic regulators have been frequently observed in tumorigenesis, serving as biomarkers and targets for cancer therapy. Here, we aimed to explore the function of epigenetic regulators in breast cancer.

METHODS

The mutational landscape of epigenetic regulators in breast cancer samples was investigated based on datasets from the Cancer Genome Atlas. The Kaplan-Meier method was used for survival analysis. RNA sequencing (RNA-seq) in MCF-7 cells transfected with control siRNA or KMT2C siRNA was performed. Quantitative reverse transcription-PCR and chromatin immunoprecipitation were used to validate the RNA-seq results.

RESULTS

Among the 450 epigenetic regulators, KMT2C was frequently mutated in breast cancer samples. The tumor mutational burden (TMB) was elevated in breast cancer samples with KMT2C mutations or low KMT2C mRNA levels compared to their counterparts with wild-type KMT2C or high KMT2C mRNA levels. Somatic mutation and low expression of KMT2C were independently correlated with the poor overall survival (OS) and disease-free survival (DFS) of the breast cancer samples, respectively. RNA-seq analysis combined with chromatin immunoprecipitation and qRT-PCR assays revealed that the depletion of KMT2C remarkably affected the expression of DNA damage repair-related genes. More importantly, the low expression of KMT2C was related to breast cancer cell sensitivity to chemotherapy and longer OS of breast cancer patients who underwent chemotherapy.

CONCLUSION

We conclude that KMT2C could serve as a potential biomarker of prognosis and chemotherapy sensitivity by affecting the DNA damage repair-related genes of breast cancer.

Impact of cholesterol-pathways on breast cancer development, a metabolic landscape

ApoB-lipoproteins and their components modulate intracellular metabolism and have been associated with the development of neoplastic phenomena, such as proliferation, anchorage-independent growth, epithelial-mesenchymal transition, and cancer invasion. In cancer cells, the modulation of targets that regulate cholesterol metabolism, such as synthesis de novo, endocytosis, and oxidation, are contributing factors to cancer development. While mechanisms associated with sterol regulatory element-binding protein 2 (SREBP-2)/mevalonate, the low-density lipoprotein receptor (LDL-R) and liver X receptor (LXR) have been linked with tumor growth; metabolites derived from cholesterol-oxidation, such as oxysterols and epoxy-cholesterols, also have been described as tumor processes-inducers. From this notion, we perform an analysis of the role of lipoproteins, their association with intracellular cholesterol metabolism, and the impact of these conditions on breast cancer development, mechanisms that can be shared during atherogenesis promoted mainly by LDL. Pathways connecting plasma dyslipidemias in conjunction with the effect of cholesterol-derived metabolites on intracellular mechanisms and cellular plasticity phenomena could provide new approaches to elucidate the triggering factors of carcinogenesis, conditions that could be considered in the development of new therapeutic approaches.

Synergistic Effect of Statins and Abiraterone Acetate on the Growth Inhibition of Neuroblastoma via Targeting Androgen Receptor

Neuroblastoma is the most common extracranial neuroendocrine tumor in childhood. Although many studies have tried to find effective treatments, there are still numerous limitations in current clinical targeted therapy. So, it is important to find new therapeutic targets and strategies from a new perspective. Our previous study reported that the androgen receptor (AR) promotes the growth of neuroblastoma in vitro and in vivo. Based on documentary investigation, we postulated that the AR–SCAP–SREBPs-CYP17/HMGCR axis may regulate cholesterol and androgens synthesis and form a positive enhancement loop promoting NB progression. Clinical samples and Oncomine database analysis proved the activation of AR–SCAP–SREBPs-CYP17/HMGCR axis in neuroblastoma. The combination of inhibitors of HMGCR (statins) and CYP17A1 (abiraterone acetate) showed synergistic effect that significantly inhibited the proliferation and migration with decreased expression of related genes detected in vitro and in vivo suggesting the dual-targeted therapy had the potential to inhibit the progression of neuroblastoma in spite of its MYCN status. This study provides new ideas for clinical treatment of neuroblastoma with efficacy and reduced toxicity.

SREBP1/FASN/cholesterol axis facilitates radioresistance in colorectal cancer

Acquired and intrinsic radioresistance remains a major challenge during the treatment of patients with colorectal cancer (CRC). Aberrant cholesterol metabolism precipitates the development of multiple cancers. Here, we report that exogenous or endogenous cholesterol enhances the radioresistance of CRC cells. The addition of cholesterol protects CRC cells against irradiation both in vitro and in vivo. Sterol response element‐binding protein 1/fatty acid synthase (SREBP1/FASN) signaling is rapidly increased in response to radiation stimuli, resulting in cholesterol accumulation, cell proliferation and inhibition of apoptosis. Blocking the SREBP1/FASN pathway impedes cholesterol synthesis and accelerates radiation‐induced CRC cell death. Our findings provide novel insights into the role of the SREBP1/FASN/cholesterol axis in radiotherapy and suggest that it may be a potential target for CRC treatment. Clinically, our results suggest that CRC patients undergoing radiotherapy may benefit from a lowered cholesterol intake.

Obesity, Type 2 Diabetes, and Cancer Risk

Obesity and type 2 diabetes have both been associated with increased cancer risk and are becoming increasingly prevalent. Metabolic abnormalities such as insulin resistance and dyslipidemia are associated with both obesity and type 2 diabetes and have been implicated in the obesity-cancer relationship. Multiple mechanisms have been proposed to link obesity and diabetes with cancer progression, including an increase in insulin/IGF-1 signaling, lipid and glucose uptake and metabolism, alterations in the profile of cytokines, chemokines, and adipokines, as well as changes in the adipose tissue directly adjacent to the cancer sites. This review aims to summarize and provide an update on the epidemiological and mechanistic evidence linking obesity and type 2 diabetes with cancer, focusing on the roles of insulin, lipids, and adipose tissue.

STARD4 promotes breast cancer cell malignancy

Breast cancer (BRCA) is one of the most common malignancies encountered in women worldwide. Lipid metabolism has been found to be involved in cancer progression. Steroidogenic acute regulatory protein-related lipid transfer 4 (STARD4) is an important cholesterol transporter involved in the regulatory mechanism of intracellular cholesterol homeostasis. However, to the best of our knowledge, the molecular functions of STARD4 in BRCA are unclear. Immunohistochemical staining and public dataset analysis were performed to investigate the expression levels of STARD4 in BRCA. In the present study, high expression of STARD4 was identified in BRCA samples and higher STARD4 expression was significantly associated with shorter distant metastasis-free survival time in patients with BRCA, which indicated that STARD4 may be associated with BRCA progression. Cell cytometry system Celigo^® analysis, Cell Counting K-8 assays, flow cytometry, wound healing assays and transwell assays were used to investigate the effects of STARD4 knockdown on proliferation, cell cycle, apoptosis and migration in BRCA cells. Loss-of-function assays demonstrated that STARD4 acted as an oncogene to promote proliferation and cell cycle progression, while suppressing apoptosis in BRCA cells in vitro and in vivo. Furthermore, knockdown of STARD4 significantly suppressed BRCA metastasis. To assess the mechanism of action of STARD4, microarray analysis was performed following STARD4 knockdown in MDA-MB-231 cells. The data were analyzed in detail using bioinformatics, and a series of genes, including E74 like ETS transcription factor 1, cAMP responsive element binding protein 1 and p21 (RAC1) activated kinase 2, which have been previously reported to be crucial genes implicated in the malignant phenotype of cancer cells, were identified to be regulated by STARD4. Loss-of function assays demonstrated that knockdown of STARD4 suppressed BRCA proliferation and migration. These findings suggested that STARD4 had an oncogenic effect in human BRCA progression.

VD3 and LXR agonist (T0901317) combination demonstrated greater potency in inhibiting cholesterol accumulation and inducing apoptosis via ABCA1-CHOP-BCL-2 cascade in MCF-7 breast cancer cells

Obesity is associated with hypercholesterolemia and is a global epidemic. Epidemiological and animal studies revealed cholesterol is an essential regulator of estrogen receptor positive (ER+) breast cancer progression while inhibition of cholesterol accumulation was found to prevent breast tumor growth. Individually, vitamin D and LXR agonist T0901317 showed anticancer properties. The present study investigated the effects of vitamin D₃ (VD₃, calcitriol), LXR agonist (T0901317) and a combination of VD₃ + T0901317 on cholesterol metabolism and cancer progression in ER+ breast cancer (MCF-7) cells. VD₃ or T0901317 alone reduced cholesterol accumulation significantly in MCF-7 cells concomitant with an induction of ABCA1 protein and gene expression compared to the control treatment. Most importantly, VD₃ + T0901317 combination showed higher effects in reducing cholesterol levels and increasing ABCA1 protein and gene expression compared to individual treatments. Importantly, VD₃ + T0901317 combination showed higher effects in increasing apoptosis as measured by annexin apoptosis assay, cell viability and was associated with induction of CHOP protein and gene expression. Additionally, the VD₃ + T0901317 exerted higher effects in reducing antiapoptotic BCL-2 while increased pro-apoptotic BAX gene expression compared to the individual treatments. The present results suggest that VD₃ and T0901317 combination may have an important therapeutic application to prevent obesity and hyperlipidemia mediated ER+ breast cancer progression.

Targeting Multiple Signaling Pathways in Cancer: The Rutin Therapeutic Approach

Multiple dysregulated signaling pathways are implicated in the pathogenesis of cancer. The conventional therapies used in cancer prevention/treatment suffer from low efficacy, considerable toxicity, and high cost. Hence, the discovery and development of novel multi-targeted agents to attenuate the dysregulated signaling in cancer is of great importance. In recent decades, phytochemicals from dietary and medicinal plants have been successfully introduced as alternative anticancer agents due to their ability to modulate numerous oncogenic and oncosuppressive signaling pathways. Rutin (also known as rutoside, quercetin-3-O-rutinoside and sophorin) is an active plant-derived flavonoid that is widely distributed in various vegetables, fruits, and medicinal plants, including asparagus, buckwheat, apricots, apples, cherries, grapes, grapefruit, plums, oranges, and tea. Rutin has been shown to target various inflammatory, apoptotic, autophagic, and angiogenic signaling mediators, including nuclear factor-κB, tumor necrosis factor-α, interleukins, light chain 3/Beclin, B cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein, caspases, and vascular endothelial growth factor. A comprehensive and critical analysis of the anticancer potential of rutin and associated molecular targets amongst various cancer types has not been performed previously. Accordingly, the purpose of this review is to present an up-to-date and critical evaluation of multiple cellular and molecular mechanisms through which the anticancer effects of rutin are known to be exerted. The current challenges and limitations as well as future directions of research are also discussed.

Nutrition, lipidic parameters, and cancer risk and progress

The aim of this literature review is to analyze the association between lipidic parameters and cancer risk and progression, as there is no clear evidence that the risk or advancement of cancer increases with cholesterol levels. Some works suggest a positive, others a negative, and still others a neutral correlation between cancer advancement or risk and cholesterol-related parameters. This lack of a simple relationship indicates the need for a more complex, multi-variable, non-linear framework correlating lipid and cancer parameters, as well as the likely existence of optimum values of lipid parameters that may pave the way to cancer therapeutic strategies that include clinical nutrition.

Microbiome-Microbial Metabolome-Cancer Cell Interactions in Breast Cancer-Familiar, but Unexplored

Breast cancer is a leading cause of death among women worldwide. Dysbiosis, an aberrant composition of the microbiome, characterizes breast cancer. In this review we discuss the changes to the metabolism of breast cancer cells, as well as the composition of the breast and gut microbiome in breast cancer. The role of the breast microbiome in breast cancer is unresolved, nevertheless it seems that the gut microbiome does have a role in the pathology of the disease. The gut microbiome secretes bioactive metabolites (reactivated estrogens, short chain fatty acids, amino acid metabolites, or secondary bile acids) that modulate breast cancer. We highlight the bacterial species or taxonomical units that generate these metabolites, we show their mode of action, and discuss how the metabolites affect mitochondrial metabolism and other molecular events in breast cancer. These metabolites resemble human hormones, as they are produced in a “gland” (in this case, the microbiome) and they are subsequently transferred to distant sites of action through the circulation. These metabolites appear to be important constituents of the tumor microenvironment. Finally, we discuss how bacterial dysbiosis interferes with breast cancer treatment through interfering with chemotherapeutic drug metabolism and availability.

Rutin and orlistat produce antitumor effects via antioxidant and apoptotic actions

Cancer is a broad term used to describe a large number of diseases characterized by uncontrolled cell proliferation that leads to tumor production. Cancer is associated with mutations in genes controlling proliferation and apoptosis, oxidative stress, fatty acid synthase (FAS) expression, and other mechanisms. Currently, most antineoplastic drugs have severe adverse effects and new effective and safe drugs are needed. This study aims to investigate the possible anticancer activity of rutin and orlistat which are both safely used clinically in humans against two breast cancer models (in vivo EAC and in vitro MCF7) and the pancreatic cancer cell line (PANC-1). Our results have shown that both rutin and orlistat exerted an in vivo anticancer activity as evidenced by the decrease in tumor volume, CEA level, cholesterol content, FAS, and the exerted antioxidant action (reduced MDA level and increased GSH content) and through histopathological examination. In addition, both were cytotoxic to MCF-7 and Panc-1 cell lines by promoting apoptosis. In conclusion, the anticancer activity of rutin and orlistat makes them promising candidates for cancer treatment alone or in combination with other anticancer drugs specially that they are used clinically with an acceptable safety profile.